High level quests showing up as level 70 quests

[Raldo]

The ShB sidequests sync to your current level. They all say Lv70 simply because that's the minimum level you're allowed to do them.

Side story quests added in patch 5.0 will now employ an automatic level adjust system known as Quest Sync.

Quests using this system will have their difficulty and EXP rewards adjusted to match your current level.

I'm not 100% certain how the system works exactly, but I'm pretty sure doing something on a lv74 should've spawned lv74 monsters, so that's a strange anecdote you have there. Without more detail of what quest you were doing, it's hard to say if it's bugged or not. I haven't encountered any problems like that so far, but I've only cleared two zones of their sidequests.

With that said, you are allowed to do the quests as one job, but turn them in on another job. So if you're stuck on that quest, just swap over to your lv80 job, kill the stuff, then turn it in on whatever other job.